The present invention relates generally to control systems, and more particularly to model predictive control employing novel techniques for optimizing energy usage and water removal in a distillation process system and a molecular sieve operation.
Many processing applications, such as biofuel production, include sub-processes where energy may be used to remove water from a product, such as biofuel, to meet the moisture specification of the final product. Multiple sub-processes may be used to remove water from the product. However, these sub-processes may be characterized by varying rates of energy usage as well as varying rates of biofuels dehydration. Therefore, balancing biofuels dehydration through multiple sub-processes, such as distillation towers and molecular sieves, is a dynamic process control challenge. A main issue in the control of such systems may be dehydrating the biofuels product to the commercial specification of moisture allowable in the product through multiple sub-processes at the minimal energy requirement. However, due to interdependencies between the sub-processes, as well as particular characteristics of each sub-process, such as equipment constraints or the availability of processing energy in each sub-process, controlling the balance between energy usage and water removal may be more complex than simply maximizing the use of the “most efficient” sub-processes.